In a post to his site Jen Segers says "goodby to controllers" in favor of request handlers. Request handlers are a concept similar to the ideas in the ADR pattern but are defined a bit differently.

If you have worked on large applications before, you might have noticed that you end up with bloated controllers sooner or later. Even if you use repositories or service classes to extract logic from the controller, the amount of dependencies, methods and lines of code will grow over time.

Let me introduce you to request handlers. The concept is very simple, yet very unknown to a lot of PHP developers. A request handler is basically a controller, but limited to one single action.

He suggests using invokable classes to build out request handlers in your PHP code, making use if the magic __invoke method to make them callable. He gives a "hello world" kind of example and talks about how Laravel and Slim already implement this idea in their routing. He then looks at how these responders help you adhere to the Single Responsibility Principle (part of SOLID) and how they make the code easier to test and simpler to refactor.